1. Field of the Invention
This invention relates to systems for sensing changes in and accumulating data relating to variable entities, quantities or conditions. More particularly this invention relates to systems of this kind wherein a sensing device utilized to sense or detect the changes involved responds thereto with a directional movement, which movement causes closures or openings in electrical circuits thereby generating binary input signals to a plurality of logic devices connected in the circuits, the outputs of which are representative, in a sequence, of the direction of change taking place.
2. Description of the Prior Art
It is well known to use electrical contacts in conjunction with a mercury thermometer to open and close electric circuits. For example, U.S. Pat. No. 2,519,853 discloses a thermostatic control utilizing a mercury thermometer having vertically spaced electrical contacts extending through the glass walls of the thermometer. When the mercury rises and covers or "wets" the contacts, a circuit is closed; when the mercury falls, the contacts are uncovered, or "dewetted" and the circuit is opened. U.S. Pat. No. 1,912,154 discloses a mercurial thermometer having contact points connected to a plurality of lead wires and resistors in a circuit of an electric fan for controlling the operation of the fan. U.S. Pat. No. 682,084 similarly describes a thermometer with embedded contacts in a resistance circuit wherein mercury, upon rising, covers contact pairs, and inserts incrementally, resistance into the thus closed electrical circuit. U.S. Pat. No. 2,356,612 discloses a temperature responsive control device including a thermometer with contacts embedded in the glass tube thereof which are connected through a rotary, manually operated switch to a motor-compressor or like device of a refrigeration system to control the operation thereof. U.S. Pat. No. 1,443,395 discloses a circuit in which lamps are operated to indicate the temperature at a remote location. U.S. Pat. No. 2,816,422 discloses a device wherein the temperature which is detected at different locations is that of the material in a bulk storage site. U.S. Pat. No. 3,505,872 discloses a device for effecting a readout in a digital counter of a measurement of temperature wherein a change in temperature produces a corresponding change in the output of an electronic oscillator. U.S. Pat. No. 489,259 discloses a thermometer with contacts embedded in the glass tube walls to set off an alarm indicating a predetermined maximum temperature has been reached.
Other prior patents have been granted over the years which are directed to temperature and/or pressure sensing devices utilizing Bourdon tubes with arms or needles attached which carries a permanent magnet on the extreme end thereof. The magnet actuates magnetic reed switches to open and close electric circuits. Similar devices are disclosed in U.S. Pat. Nos. 3,273,139 and 3,656,082. In U.S. Pat. No. 3,656,082, a thermostat is disclosed in which the temperature or pressure sensitive element is a bimetal strip in the form of a coil with a permanent magnet mounted on the end of the coil strip in cantilever fashion, providing a magnetic reed switch for opening and closing an electric circuit. U.S. Pat. No. 3,976,963 discloses an array of magnetic reed switches which are operated to open and close electric circuits by a moving permanent magnet. Other U.S. patents disclosing related subjects are: U.S. Pat. No. 3,464,047 for a magnetic reed switch operative by the melting of a frozen liquid in which they are embedded; U.S. Pat. No. 3,721,929 for a battery of reed switches in side-by-side array operated by a moving magnet; U.S. Pat. No. 3,859,651 for a plurality of magnetic reed switches operable to produce a visual display of the degrees of angle of a boom member of a lifting crane; and, U.S. Pat. No. 3,419,731 for a plurality of reed switches arranged on a curved path. U.S. Pat. No. 4,061,901 discloses a telemetering system in which a magnet is supported on a rotating shaft and, in rotating, closes and opens electrical circuits by closing and opening magnetic reed switches, or sensors, positioned along the magnet's path of rotation. Each switch or sensor is connected to an input of two different logic devices, i.e., flip-flops so that data bits stored in each flip-flop are determined by the sequential activation of two or more of the sensors. Each data bit stored in a flip-flop is a digit of a three-digit binary code, and the output of each flip-flop is connected to an AND-OR-INVERTER, the output of which, connected to a binary coded decimal (BCD) up-down counter, determines whether the counter counts positively or negatively. Thus, the signals produced by the switches or sensors are fed to the counter via the inverter and are stored and counted therein. The counter includes a "clock" which receives a pulse or voltage through an increment line activated in response to changes in the sensors. The information stored in the counter is then dispensed or recorded as desired. In one application disclosed the information is automatically transmitted by radio whenever a change in that information occurs, thus being useful in connection with remotely located information gathering or accumulating devices. It will be appreciated that the system disclosed in this patent is ideally suited for application of the present invention and such is contemplated.
Thus, it is evident that many prior art devices are known which utilize mercury column and rotating arm thermometric or pressure sensitive devices to open and close electric circuits for controlling the operation of, or measuring the temperature or pressure of implements, devices and systems and their environments. However, nowhere in this prior art is it known to use such sensing devices in an incremental temperature data accumulator system comprising logic circuits with connected gating devices to produce a binary signal code of different binary significances in a sequence representative of the changing quantities being detected at a remote location, i.e., increasing (up) or decreasing (down).